Battery charger



April 25, 1950 R. c. GILBERT ETAL BATTERY CHARGER Filed Aug. 19, 1949 7 5 R U S mfimm m m w w VG/ I T w. M A I new ML I 5/5, 0 5% 3 mg M a w R. C. GiLBER T ETAL April 25, 1950 BATTERY CHARGER 3 Sheets-Sheet 2 Filed Aug. 19, l949 In if H Ho 6 a! INVENTORS RUSSELL C. GILBERT LESTER L.'VV/L5RECHT MMWQ ATTORNEYS April 25, 1950 mB ETAL 2,505,614

BATTERY CHARGER Filed Aug. 19, 1949 3 Sheets-Sheet 5 12/ 2 414' ,/49 Jar-3a //9 I32 Ago INVENTORS RUSSELL. C. G/LBERT LESTER L. l/V/LBRECHT Av-ToRA/E Y8 Patented Apr. 25, 1950 UNITED STATES PATENT OFFICE 2,505,614; BATTE HA GER Russell 6. Gilbert, Stillwater, and Lester Wilbr'echt, St. Paul, Minx-1., assignors to Telex Inc... Minneapolis, Minn}, a corporation of Minnesota Application August 19, 1M9, erial No. 111,3!)4 12 Claims. (01. 32 -4) This invention relates to battery chargers and particularly to a battery charger which may be used by inexperienced persons for what is known as the re-charging of hearing aid A and B cells. While, strictly speaking, it is not possible to recharge primary cells; this term has come into common use for the process of renovating hearing aid cells, which might more properly be called electrical depolarization. Since the term recharge is in common use, it will be'used herein.

The A cell and B battery of hearing aids are relatively small in size, and since the hearing aids are worn continuously or almost continuously the drain on these c'ells'is relatively heavy. In years past it has been customary merely to replenish the cells and to discard the old and discharged cells, but more lately it has been found possible to recharge the cells and to obtain great ly increased life for them by virtue of such recharging operation. Hearing aids are worn 'for the most part by persons of little experience in electrical matters and by older persons, and accordingly any battery charging device suitable for their use must be of the utmost simplicity.

It is an object of the present invention to provide a combined A cell and B battery charging device for hearing aid recharging service of utmost simplicity and capable of being used by inexperienced and elderly persons without harm to the cell or danger tothe user.

It is a further object ofth'e invention to provide a hearing aid 'batt ery' recharging device which is completely safe to use and which does not present any live terminalsto the user when in loading condition.

It is a further object of the invention to provide an improved A cell'and B battery charging device with indicators so as to show when the device is in operation;

Qther and further objects of the invention are those inherent in the apparatus herein illustrated, described and claimed.

The invention is illustrated with reference to the drawings in which corresponding numerals refer to the same parts and in which Figure 1 is a plan view of the device with the cover lifted;

Figure 2 is a top view of the device with the cover lifted and with A and B cells both in place for charging; i Figure 3 is a sectional view along the line and t direction of rr ws Qi Finn's 2 hawing an A cell in charging position and the cover closed;

Figure 4 is a sectional view along the line and in the direction of arrows i''of Figure 2 showing' a B" battery 'in charging position and the cover closed;

Figure 5 is a plan view of the apparatus showing the case removed so as to expose the working elements'of the device and taken along a section line, as at 5-5 of Figure 3, with the battery removed;

Figure 6 is a sectional view taken in the direction of arrows 6- 3 of Figure 5;

Figure 7 is a sectional view through the hingeswitch mechanism of the device, taken in the direction of arrows l i of Figure 6;

Figure 8 is a, wiring diagram of the standard type'of battery charging set for use'on'110-volt alternating current circuits;

Figure 9 is a wiring device of a slightly modiiied form suitable for use on higher voltage circuits, such as 220-voltalternating' current cirwit Referring to the drawings, the battery charger of the instant invention includes a base member [I], preferably 'of plastic sheet; and'a molded cover 20 which fits down around the base when the cover is applied to the base. 'The cover is provided with ihterior molded bosses 2!, '22, 2'3 and 24 through which" screws are inserted through holes 2lA, 22A, 23A and 24A in the bottom so as to hold the molded cover to the base.

the base It] there are'four inserts 25 of rubher "which serve as feet upon which "the base it rests when the unit is set down.

At the rear ofthe'base are two posts 26 and Z'Lea'c'h ofwhich serves as a mechanical support and electrical conne tion; It wiil be noted that the post 2t is bent over at its bottom 28 and is attached to the base by means of a small bolt 29, the post 2'? beings'imilarly bent over at the base portion 3i] and attached by a small bolt 3|. The up per end of each post is likewise bent over, as shown at 32 for post 25 and for post 21. The bentovr portions and are attached togetherby an insulating" strip 35 and the bent over portions 32' and 33"each serve to support a pair of switch blades. Thus, there is provided a switch blade 35 which teaserr'ectly upon the bent over portion 32' of post 25. Above the Switchblade 35 is a strip of insulatioh 38 and above it asecond switch blade 89. A through-bolt and electrical connect n is provided'at 40 which serves as a terminal for t e upper switch blade 39. The boltfit is'etherwlse insulated throughout its length from the switch blade 36. Another bolt 4| is insulated from the lower switch blade 36 and portion 32 of the post. On the post 21 there is a similar arrangement of switch blade, the lower blade 42 resting directly upon the bent over upper portion 33 of the post. Upon the switch blade 42 there is a strip of insulation 43 and upon it rests the upper switch blade 44. The switch blades and insulation in assembled relation are held by a pair of bolts 45 and 47 which serve not only as a fastening, but also as an electrical terminal for the upper switch blade 44, the bolt 45 being otherwise insulated from the lower switch blade 42 and the portion 43 of the post. Another bolt 41 is passed through the assembly and is likewise insulated from the lower switch blade 42 and portion 33 of the post. The incoming electrical circuit indicated by the double wire cord L1L2 enters the unit through a grommet 48 at the rear portion 49 of the cover 26 and one of the incoming power lines L1 is connected to the boltterminal 40, whereas the other L2 is connected to the bolt-terminal 45. The pair of switch blades 36 and 39 are normally spaced from each other, as are blades 42 and 44. Each pair, viz. 36 and 39 and also 42 and 44, are pushed together by member 53 as now described.

The upper portion 59 of the case is provided with a flat bOSs area extending downwardly from its highest part. This boss 5| is provided with a rectangular slot 52 and in the slot there slides vertically a plastic button 53 which has a midfiange at 54. Below the flange 54 there is a plate 56 which is held in spaced relation to the bottom of the boss 5| by a pair of collars 5'1 and screws 58 which enter the lower surface of the boss from the inside of the unit. The plate 56 has a rectangular opening 59 centrally therethrough so as to be aligned with the rectangular opening 52 and accordingly the slide member 53, which is also of rectangular cross section, is permitted to move up and down, the upper limit of movement being defined by engagement of the flange 54 with the under surface of the boss 5| and the lower limit of movement by the engagement of the flange 54 for the upper surface of the plate 56. The rectangular block 54 is of suflicient cross dimension so that it engages and rests upon the upper surfaces of each of the switch blades 39 and 44 and is adapted to press them down simultaneously. When the slide 53 is depressed, by the action of cover member 66 which will be described, the switch blades 39 and 44 are pressed downwardly, thus causing each of them to establish contact with its cooperating switch blade 36 and 42, respectively. The rectangular slide 53 has a sufiiciently loose fit so that no binding occurs. When the slide 53 is not pressed down, the springiness of the switch blades 59 and 44 causes the slide 53 to be lifted and the contacts to be broken.

The cover member 60 is preferably of clear plastic sheet pressed to the shape shown in the drawings, so as to cover the working parts of the battery charger and the batteries when they are in place being charged, and yet permit the user to see the batteries in place. The cover is hinged to the case at 6| and on the inside of the hinge there is provided a bent down U-shaped hook piece 62 so arranged that when the cover is in the closed position, as shown in Figures 3 and 4 and in dotted lines in Figure '7, the tip 64 of the hook will move into engagement with and will press down upon the upper surface of the vertical rectangular slide 53 and cause it to be pushed downwardly to switch closing position. Yet when the cover is elevated to the position shown in Figures 1, 2 and 6, and in full lines in Figure 7, the tip 64 is retracted ofi the surface of the slide 53 and the inherent springiness of the switch contacts 39 and 44 causes the slide to be lifted and the contacts separated, as previously described. Hence, by merely lifting the cover the main switches 3639 and 4244 of the unit are permitted to open, thus opening all circuits to the battery charging mechanism. Yet when the cover, which is of clear plastic, is moved to the closed position, as shown in dotted lines in Figure '7, the circuits are re-established and the battery charging operation ensues.

Upon the rear central portion of the base [6 there is mounted an insulating block 66 having slots 6'! and 69 milled in it to receive a pair of battery contacting and switching blades 69 and vl9, respectively. The block 66 also has some wider slots 12 and 13 therein. The blade 59 is held by a pivot pin 14 which also serves as a contact, and the blade 19 is held by a pivot pin 15 which likewise serves as a contact. Around the pin 74 is Wrapped a spiral spring having tip portion 'l6l6 which bears upon the upper surface of the base, and a central U-port.on ll which reaches across the upper portion of the blade 69, causing it normally to be pushed downwardly. The blade 69 can, however, be lifted manually against the pressure of the spring ii for switchin; and battery inserting operations preparatory to charging. Similarly, a spring member T9 838I rests upon and presses downwardly on the switch blade l9 causing it likewise normally to be moved in the downward position. Yet blade 16 can be lifted up manually for inserting the battery and for switching arrangements.

Each of the blades 65 and '55 has, in cooperation therewith, a rest-battery contact strip which is mounted upon the base and extends through the cover 29 as follows: The rest-contact strip for cooperatng with the blade 59 is indicated generally at 83 and has a rear upturned portion 84 of comparatively narrow width, and a front broad upwardly slanting portion 65. The portion 84 is of such a height that it comes up close to the slot 86 in the battery recess 81 for the B battery so as to be engaged by strip 69 when nothing is, in recess 61, and the upwardly slanting portion is of such a width and slant that it comes up through the slot 88 in the base of the recess 87 and rests against the portion 89 of the battery recess where it forms the B+ contact for B batteries placed in the recess 87 for charging. It will be noted that the blade 69 has a rounded tip portion 99 that is slotted at 9| so as to leave a finger 92 upon which an insulating plastic grip 93 can be attached. The blade 99, which is in battery charging position in Figure 4, extends thus outwardly through the slot 65 and the portion 99 contacts with the negative terminal B- of the B battery indicated B, whereas the slanting portion 85 of the contact and switch post generally designated 83 serves as a rest against which the B battery slides and makes contact and constitutes the B+ terminal. The spring ll- 53 always exerts a rotating force in the direction of arrow 85, thus maintaining the contacts previously described. When the B battery is removed from the recess 37, the spring ll causes the blade 69 to move down to the dotted line position, as shown in Figure 4, thus causing it to engage upon the upper edge 84' of the contact and terminal arrangement 83, accordingly establishing a contact from the blade 69 to the terminal 83.

ate-5,614

immediately below and in front of the portion 88 of the case there is a'space" 96' in which a small gas-filled glow-type lamp 61' is positioned. The lamp 91 is an indicator lamp and through the adjacent portion 98 of the case there is inserted a clear plastic rod-button, such as Lucite rodbutton 69, which reaches from a position closely adjacent the lamp 61 through the case. When the lamp 61 is illuminated enough light passes outwardly through the Lucite rod-button 59 so as to make the illumination of the lamp visible from the front of the case for indication purposes.

Similarly, referring to Figures 1, 2 and 3, a recess I66 is provided for the A cell charging, the recess I66 having a slot IiII through which the switch blade lilextends, the blade terminating in a rounded tip I02 having a slot'at I03 and leaving finger I04 upon which the plastic insulating grip I65 is attached. Likewise, beneath the recess I66 is a terminal switch and contact arrangement generally designated I06 having an up-turned relatively narrow inner portion I61 terminating at I61 adjacent the lower end of the-slot I6! and an upwardly slanting portion I68 which extends out through the slot I69 and rests against the fiat inclined portion N6 of the base of recess I66, forming .a terminal against which the positive terminal A-lof the A cell, designated A, is adapted to be rested, and with which it establishes contact. The rounded portion I02 of the blade 16 contacts against the opposite end of the A cell which is the A terminal. The spring 8| likewise normally causes the blade 16 to be pressed in the direction of arrow III and immediately below the slanted portion IIIl of the A cell recess, there is positioned an indicator light II3 of the glow type and through the adjacent portions II4 of the case there is inserted a Lucite rod-button II which conveys light from i the lamp I I3 to the exterior of the case for indication purposes.

Centrally across the base I 6 there is a contact and mounting strip II6, upon the center portion of which there is mounted a vertically disposed rectifier unit II1 having an upper terminal II8 which is, of course, separate from the strip II6. Strip H6 is the positive terminal of the rectifier, and strip H8 is the negative terminal of the rectifier I I1.

Referring to Figures 5, 6 and 8, the circuits through the rectifier may be traced as follows: The incoming power circuits Li-Lz have previously been traced through the switches 36-39, which controls line L1, and 42-44 which controls L2. Thus, when the switch 36-39 is closed, power from line L1 is applied to the post 26 and hence to its terminal base 28 and likewise when the switch 42-44 is closed, power is applied from line L2 to the post 21 and terminal portion 36. From these portions the circuit then continues. From the portion 28 of post 26 (line Li) a circuit extends through conductor I to the negative terminal I I8 of rectifier I I 1 and thence vertically downwardly through the rectifier to the positive rectifier treminal, which is the same as the contact strip I'IB across the middle of the instrument. From the soldered junction I29 on the strip I I6 a circuit extends through conductor I I9, resistor I35. indicator light I2I andline I22 to the portion and thence through post 21 and switch contacts 42-44 to line L2: It may be noted that the lamp I2l" is located centrally in respect to the front of the instrument. It is spaced along a line with lamps H3 and 91, previously mentioned, and the lamp' I2I is likewise provided with a Lucite rod-button I34 which conveys the light from the lamp I2I out through a hole the case to form an indication for the user. The light IN is illuminated whenever the switches 36-39 and 42-44 are closed, whenever the case top 66 is moved downwardly, as previously described.

The lamp I2I is physically mounted upon the base It by means of its relatively stiff terminal conductors I23 and I24. These are soldered to tiny cup rivets that are inset at I25 and I29 through the base I6, and hence the cup rivets I25-I26 serve as terminals to which the conductors are soldered and not only serve as electrical terminals, but as physical supports. Lamps 85 and I I3 are similarly mounted.

From the junction I29 on strip IIB a circuit also extends via conductor I21 through resistor I28 to the contact and terminal arrangement 83. The contact and terminal strip 83, it will be remembered, serves as the B+ contact 85, against which the B battery is rested for charging purposes. If it is assumed that a B battery is in charging position (Figure 4) a circuit continues between the B-lterminal 85 and the rounded portion 96 of the strip 69, the electrical terminal of which is the pivot post 14 and from 14 a circuit extends via the conductor I 30, to junction I33, thence through resistor I31 and conductor I32 to portion 36 of terminal 21 and via switch 42-4 5 to line L2. From contact and terminal 83-85 a circuit extends through line I36, resistor I31 to mounting stud I38 and thence 1 through indicator light 91, previously mentioned,

to mounting stud I36 from which the circuit continues via line I46 through junction I33 and line I to the movable contact strip 69 previously mentioned. When a B battery is in place for charging, as shown in Figure 4 and Figure 2, the movable contact 66 engages the negative terminal of the B battery and the strip 85 engages the positive terminal of the B battery, thus placing the indicator lamp 91 and its resistor I31 in series across these terminals of the battery. The voltage drop across the battery B is insuflicient to i1- luminate the lamp 91, and lack of illumination therefore indicates that the contacts of the charger have established proper charging connection with the battery B. If the lamp 91 is illuminated while a battery B is in place for charging this indicates that either contact 69 or strip 85 are not establishing proper contact and that the charging circuit is incomplete.

From mounting stud I42 on the contact strip I'I6 a circuit extends via line I43 through resistor I44 and line I45 to the contact and connection strip let, the contact portion I68 of which serves as the A+ contact against which the A+ terminal of the A cell is placed during battery charging operation, as shown in Figure 3.

If it is assumed that an A cell is in place, as shown in Figure 3, the circuit then continues to the A- terminal which is in contact with the portion I62 of the movable contact member 16 through which the circuit continues to its pivot 15 and thence through line I46 to junction I41 through a continuation of line I46 and thence through resistor I48 and line I49 to junction I56 and to the contact portion 36 of the post 21, thence through the post and through movable contacts 424 1 to line L2. From the contact and terminal I06 a circuit extends over line I5I through resistor I52 to terminal and mounting stud I53, thence through glow lamp 3' to terminal and. mounting stud I54 and through line I55 to junction I41 and thence through line I46 to movable contact 'l0|02. Accordingly, when an A cell is in recess I for charging operation, .as shown in Figures 2 and 3, a potential is es- ;tablished across the A cell between movable contacts I0I02 and stationary contact I08. The potential across the A cell is not suflicient to illuminate the glow lamp H3 and hence lack of illumination of lamp I I3 through the Lucite rodlbutton II5 shows that proper charging connec- :tion has been established. If lamp H3 is il- 'luminated while an A cell is in place for charging, xthis will indicate that either the contact 'I0-I02 -or contact I08 is not establishing proper charg- ;ing connection with the cell.

From terminal M2 on the contact strip lit, which is the positive terminal of the rectifier i I, :a circuit extends over line I58 to condenser I60 :and thence over line PM to junction I53 to contact portion of the post 2? and through switch -=contacts d2-4 3 to line L2. The condenser IEO oan, optionally, be omitted where smoothness of power output is of no importance.

The circuits traced have been identically num- Ibered, Figures 5 and 8. Figure 8 operates very satisfactorily for relatively low voltage alternating current circuits, such as ll0-volt 50-60 cycle circuits. It will be noted that when no battery is in place in the B battery charging depression 8?, the movable contact blade 69 moves in the direction of arrow 95 and engages the upturned portion B5 of the contact 83, thus short-circuiting the circuit of indicator lamp 9i. A circuit, however, is maintained at this time through the B battery charging network beginning at terminal Fit-4 32 through resistor :28, through movable contact 35 to contact portion 90 and connection I30, resistor iii! to the contact portion 30 of the post 2?. Charging current is maintained through this circuit so that approximately the same total charging current will flow through the rectifier, as determined by the resistances HS and I3I. Similarly, when an A cell is not in recess I023 for charging, the movable contact 70 engages the contact It? and establishes a circuit which likewise flows frOm terminal I8i42 through resistor EM, contact 50%, contact I02, "movable contact l0, resistor E68, line M9 to terminal 30 on post 2?. The load through the rectifier is, therefore, never reduced below the amount of current flowing through resistors I23 and l3l in series and this serves to protect the rectifier against deterioration due to total open circuiting conditions.

For use on higher voltage alternating current circuits the apparatus is slightly modified as shown in the wiring diagram Figure 9, which is identical with that shown in Figure 8 and therefore need not be described, except for the following particulars: In place of a single rectifier cell IIl' there is added in addition in series a second rectifier cell H1 and the flexible cord constituting lines L2 and L1 is made of a resistance material providing approximately 1000-1500 ohms resistance in the cord itself. The resistance in the cord L1 and L2 of Figure 9 and the additional rectifier cell I ii, enables the use of the circuits on higher voltages such as 220-volt 50 or 60 cycle circuits.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments herein.

What we claim is:

1. In a battery charging device having a source of unidirectional current, a case having a recess for receiving the unit to be charged, said recess having terminals, means therein for contacting the terminals of the unit for charging, a swinging cover mounted on said case so as to cover said recess and to be movable to a position to expose said recess, means for completely de-energizing he terminals when the cover is swung to expose the recess and to energize the terminals when the cover is swung to cover said recess.

2. The battery charger device of claim 1 further characterized in that said terminal means includes one mounted for movement to a position engaging the other terminal so as to complete an electrical circuit therethrough when no unit is in the recess.

3. The batter charger device of claim 1 further characterized in that glow lamp means is mounted in the case and is connected across said terminal means so as to be energized and the glow lamp means illuminated when a unit is in the recess being charged, said case being apertured so the glow lamp means when illuminated is visible from the exterior or" the case.

i. A battery charger device having alternating current supply line and a rectifier, a case, said case being shaped to receive a unit to be charged and provided with terminals, connected to said rectifier and alternating current supply for charging positioned against the case, a cover hinged to the case and shaped to cover a unit during charging when the cover is swung against the case and switch means on the case actuated by said hinged cover and connected in circuit with said alternating current suppl line for de-energizing the charger device when said cover i swung away from the case.

5. The battery charger of claim 4 further char acterized in that said cover is transparent.

6. A battery charger device comprising a case having a recess therein shaped to receive a unidirectional voltage unit to be charged, said recess having a first terminal at one end thereof, a second terminal mounted in said case for movement toward and away from said first terminal, said second terminal extending through the case wall forming said recess and being biased to move into engagement with said first terminal when no unit is in the recess.

7. The battery charger of claim 6 further characterized in that said second terminal is pivotally mounted within the case and constitutes a blade extending through a slot in the case wall.

8. In a battery charger, a flat base, a pair of stiif conductors extending upwardly from the base, spring contact means mounted on each post, presser bar means mounted so as to be movable vertically to push said spring contact means to close circuits therethrough to said posts, a case connected to and covering said base, said presser bar means being slidabl-e through a slot in said case, a swinging cover mounted on the case for swinging movement from a position away from said case to a position covering a portion of said case, said cover having a part thereon engageable with said presser bar to close the switch means when the cover is swung to a position covering a portion of said case.

9. The battery charger of claim 8 further characterized in that the portion of the case covered by said swinging cover has a longitudinal recess therein for receiving a unit to be charged when laid in said recess, said recess being provided with a fixed contact against which a unit may rest and with which one terminal of the unit contacts for charging, and a blade mounted within the case and projecting through a slot extending lengthwise of the recess for contacting another terminal of said unit, said blade being spring biased towards said fixed contact.

10. The battery charger of claim 9 further characterized in that the portion of the case covered by the swingin cover has two longitudinal recesses in one of which A cells may be placed for charging and in the other of which B batteries may be placed for charging, each recess provided with fixed and swinging blade terminals.

11. A battery charger comprising a, pair of alternating current supply lines each equipped with a switch for opening and closing the same, 2. rectifier connected to one of the alternating current lines for rectifying the current flowing therethrough, parallel charging circuits each connected between said rectifier and the other alternating current supply line, each parallel charging circuit including a resistor, a first terminal for REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,004,101 Stone Sept. 26, 1911 1,425,689 Powell Aug. 15, 1922 2,000,571 Oswald May 7, 1935 2,036,547 Siemon Apr. '7, 1937 2,082,168 McKinley June 1, 1937 2,199,322 Skinner Apr. 30, 1940 2,375,866 Nelms et a1 May 15, 1945 2,410,527 Schinske Nov. 5, 1946 2,451,726 Fry Oct. 19, 1948 2,483,673 Robinson et al. Oct. 4, 1949 2,491,031 Burgess Dec. 13, 1949 

